Dave,
As I'm sure you're well aware, most patents are only worth the paper they're written on. I'm not the brightest mechanical engineer around, but give me a few days and I can come up with a way around 99% of the mechanical utility patents I've seen. It's not that the patents were poorly constructed, it's just the nature of the design process.
Even though they're mostly worthless in the long run, there's two reasons that large companies still file lots of patents. First, they have lots of attorneys on retainer with nothing better to do. And second, they have a fiduciary obligation to their shareholders to at least make a token effort to protect their IP.
As for Sikorsky's VDR, they abandoned the idea a few years back when it became obvious that the complex device could never likely be made reliable enough for actual service. However, they have been asked to take a second look at the concept as part of the US military's JFTL study program.
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